Answer:
L=55.9m
Explanation:
The equation for the period of a simple pendulum is:

In our case what we know is the period and the acceleration of gravity, and we need to know the length of the pendulum, so we can write:

Which for our values is:

The correct answer is option #4. The greatest obstacle to developing solar energy is large areas required to collect sufficient energy. Solar energy is the energy that is the sun is producing and being converted into thermal energy that can be used for everyone's daily lives.
Answer:
The friction of the piano and the weight
Explanation:
Work is performed while initially lifting books off the floor. The work is due to gravity.
Hope this helped! i’m not sure if it’s right. it honestly bored so i’m answering questions.